US1998240A - Process for the preparation of dibenzothiazyldisulphide from 2-mercaptobenzothiazole - Google Patents
Process for the preparation of dibenzothiazyldisulphide from 2-mercaptobenzothiazole Download PDFInfo
- Publication number
- US1998240A US1998240A US732466A US73246634A US1998240A US 1998240 A US1998240 A US 1998240A US 732466 A US732466 A US 732466A US 73246634 A US73246634 A US 73246634A US 1998240 A US1998240 A US 1998240A
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- US
- United States
- Prior art keywords
- nitric acid
- mercaptobenzothiazole
- dibenzothiazyldisulphide
- kgms
- oxidation
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D277/00—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings
- C07D277/60—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings condensed with carbocyclic rings or ring systems
- C07D277/62—Benzothiazoles
- C07D277/68—Benzothiazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2
- C07D277/70—Sulfur atoms
- C07D277/76—Sulfur atoms attached to a second hetero atom
- C07D277/78—Sulfur atoms attached to a second hetero atom to a second sulphur atom
Definitions
- This invention relates to a process for the preparation of dibenzothiazyldisulphide from 2- mercaptobenzothiazole.
- mercaptobenzothiazole may be converted in a simple manner into dibenzothiazyldisulphide by treating the same in the manner hereinafter described at room temperature and without the supply of external heat with'aqueous nitric acid.
- mercaptobenzothiazole can be converted into the corresponding disulphides by causing oxygen or oxygen-containing gases to react with an aqueous suspension of the mercapto compound in the presence of nitrogen oxides or nitrous acid which serve as oxygen carriers. It is further known that mercaptothiazoles can be oxidized to disulphides with the aid of dilute nitric acid at boiling temperature. Pure products cannot be obtained by these known processes, so that the products resulting from the oxidation have to' be subjected to a further special purifying process. Moreover, during the treatment at boiling temperature, a large quantity of nitric acid is lost unused.
- the mother liquor is employed for suspending the next batch, fresh nitric acid being added to the suspension to replace the used up acid.
- the mother liquor may be returned to the process as often as desired.
- the conversion is with advantage carried out in a closed vessel, in which a slight excess pressure is maintained by suitable closure so that the resulting NO may escape.
- the nitric acid employed for the oxidation must have a minimum concentration of about 7%, if it is desired to carry the oxidation through to completion. Stronger acids may, of course, also be employed, the operation being, for example, carried out with an aqueous nitric acid, containing 7 to 20% of HNO3. The process in these cases is carried out as described in the foregoing examples and the water and nitric acid are used in such proportions that the resulting nitric acid has the desired concentration.
- the oxidation may be effected both with the theoretical quantity of nitric acid and also with an excess.
- a process for the preparation of dibenzothiazyldisulphide from Z-mercaptobenzothiazole which consists in treating Z-mercaptobenzothiazole at room temperature and without the supply of external heat with aqueous nitric acid having a concentration of at least 7%.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Description
Patented Apr. 16, 1935 UNITED STATES PATENT OFFICE Gerhard Kiillner, Idaund Marienhutte, Germany, assignor to Silesia Verein Chemischer Fabriken, Idaund Marienhutte, near Saarau,
Silesia, Germany No Drawing. Application June 26, 1934, Serial No. 732,466. In Germany July 18, 1933 4 Claims. (Cl. 260-) This invention relates to a process for the preparation of dibenzothiazyldisulphide from 2- mercaptobenzothiazole.
. According to this invention it has been found that mercaptobenzothiazole may be converted in a simple manner into dibenzothiazyldisulphide by treating the same in the manner hereinafter described at room temperature and without the supply of external heat with'aqueous nitric acid.
It is known that mercaptobenzothiazole can be converted into the corresponding disulphides by causing oxygen or oxygen-containing gases to react with an aqueous suspension of the mercapto compound in the presence of nitrogen oxides or nitrous acid which serve as oxygen carriers. It is further known that mercaptothiazoles can be oxidized to disulphides with the aid of dilute nitric acid at boiling temperature. Pure products cannot be obtained by these known processes, so that the products resulting from the oxidation have to' be subjected to a further special purifying process. Moreover, during the treatment at boiling temperature, a large quantity of nitric acid is lost unused.
The following examples serve to illustrate how the process of this invention may be carried into effect:
1. 167 kgms. of Z-mercaptobenzothiazole are mixed with a nitric acid, which has been prepared from 200 kgms. of Water and 34 kgms, of nitric acid (62% HNO3) The mixture is periodically kneaded and after about 8 to 10 hours the oxidation is completed. The mixture is stirred with water and filtered and the solid matter washed with water. About 165 kgms. of dibenzothiazyldisulphide of freezing point 172 to 178 are obtained.-
2. 167 kgms. of 2-mercaptobenzothiazole are suspended in 400 kgms. of water. 68 kgms. of nitric acid (62% I-INOs) are added to the suspension with stirring. The conversion is completed after about 10 hours and 165 kgms. of dibenzothiazyldisulphide of freezing point 173 to 177 C. are obtained.
The mother liquor is employed for suspending the next batch, fresh nitric acid being added to the suspension to replace the used up acid. The mother liquor may be returned to the process as often as desired. The conversion is with advantage carried out in a closed vessel, in which a slight excess pressure is maintained by suitable closure so that the resulting NO may escape.
3. 167 kgms. of 2-mercaptobenzothiazole are mixed in a closed vessel, if necessary with stirring, with a nitric acid which has been prepared from 400 kgms, of water and 68 kgms. of nitric acid (62% HNOs). During the conversion an excess pressure of 0.2 to 1.0 atmospheres is maintained in the apparatus. The oxidation is completed after about 5 to 8 hours and the product is worked up as described in Example 2. The mother liquor may be returned to the process as often as desired, exactly as described in Example 2. The yield and purity of the resulting disulphide are the same as those of the products obtained in the preceding examples.
The nitric acid employed for the oxidation must have a minimum concentration of about 7%, if it is desired to carry the oxidation through to completion. Stronger acids may, of course, also be employed, the operation being, for example, carried out with an aqueous nitric acid, containing 7 to 20% of HNO3. The process in these cases is carried out as described in the foregoing examples and the water and nitric acid are used in such proportions that the resulting nitric acid has the desired concentration. The oxidation may be effected both with the theoretical quantity of nitric acid and also with an excess. Of the nitric acid employed in excess, only a quantity corresponding to the equation GRSH+2HNOs=3R-S-S R+4HzO+2NO is each time usedup. Theoretically this quantity amounts to of a mol of nitric acid per one mol of mercaptobenzothiazole.
I claim: 7
1. A process for the preparation of dibenzothiazyldisulphide from Z-mercaptobenzothiazole, which consists in treating Z-mercaptobenzothiazole at room temperature and without the supply of external heat with aqueous nitric acid having a concentration of at least 7%.
2. A process as claimed in claim 1, wherein the nitric acid employed has a concentration of from 7 to 20%.
' 3. A process as claimed in claim 1, wherein the operation is carried out in a closed vessel under a slight excess pressure.
4. A process as claimed in claim 1, wherein an excess of nitric acid is employed for the oxidation and the non-used up,nitric acid is employed for the oxidation of further quantities of mercaptobenzothiazole.
GERHARD KALLNER.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE1998240X | 1933-07-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US1998240A true US1998240A (en) | 1935-04-16 |
Family
ID=7935370
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US732466A Expired - Lifetime US1998240A (en) | 1933-07-18 | 1934-06-26 | Process for the preparation of dibenzothiazyldisulphide from 2-mercaptobenzothiazole |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US1998240A (en) |
-
1934
- 1934-06-26 US US732466A patent/US1998240A/en not_active Expired - Lifetime
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